This invention relates to multilamp photoflash units, and more particularly, to photoflash units having a printed circuit board with a flat connector tab projecting therefrom.
Presently available multilamp photoflash units of the cube-shaped type, such as those referred to as flashcube and magicube, have means for securely holding the flash unit within the receiving socket of a camera or photoflash accessory. More specifically, these units are provided with a base retaining post having either protuberances or depressions symmetrically disposed on four sides of the post which are releasably engaged by resilient fingers within the receiving socket upon insertion, thereby providing a secured detent latching. Such base latching arrangements are described in U.S. Pat. Nos. 3,327,106; 3,602,618; 3,612,849; and 3,691,508.
Another multilamp photoflash unit presently on the market and referred to as a flip flash includes a printed circuit board with a flat connector tab which is partially enclosed in an extension of the unit housing. In addition to protecting the connector tabs, the housing extension also is configured to have recesses and protuberences for facilitating secure detent latching within a receiving socket. For example, a flip flash array is described in U.S. Pat. No. 3,935,442, and the socket latching arrangement for the flip flash unit is described in U.S. Pat. No. 3,941,447.
In the case of another currently popular linear array of photoflash lamps referred to as a flash bar, however, the connecting means for the unit comprises a projecting flat connector tab of a printed circuit board, and retention of the unit in a receiving socket is provided solely by the pressure of resilient contacts against flat conductor terminals on the connector tab. There is no provision for secure latching by means such as a detent arrangement. The connector and socket arrangement for the flash bar is described in U.S. Pat. Nos. 3,757,643 (FIG. 3 thereof) and 3,598,985 (FIG. 4 thereof).
U.S. Pat. No. 3,430,545 describes another linear photoflash array in which a depending connector tab has a plurality of selective terminals on the front side of the tab, while a single elongated common terminal strip is disposed transversely across the rear side of the tab. A plurality of recesses are provided through the common terminal strip on the rear side of the tab, and when the unit is inserted in the corresponding receiving socket, a spring loaded contact, or electrode, within the socket is provided with a row of projections which snap into the complimentary recesses of the tab so that the unit is held against unintentional displacement. U.S. Pat. No. 3,473,880 shows another linear array having but one terminal on each side of a depending tab. Each terminal appears to be provided with an indentation, perhaps for retaining purposes.
It is a purpose of the present invention to provide means for increasing the holding power of a receiving socket upon any photoflash unit having an interface consisting solely of a flat connector tab, such as that of the flash bar. Further, it is desired that the increased retention be obtained without involving the electrical tab terminals and socket contacts in a detent arrangement. Also, the approach should be suitable for circuit board and tab configurations wherein all conductor patterns and terminals are on the same one side of the board.